In order to study the effects of radiation on a sample, a controlled dose of radiation must be introduced into the sample, or a localized area thereof. When the sample is relatively small (e.g., biological cells, integrated circuit device components, and the like), the radiation device should be capable of delivering a radiation beam that is on the same, or similar, scale. For example, in radiobiological experiments where single cells are to be dosed, the ideal irradiator should have a compact radiation beam with a cross-sectional dimension on the order of about 1 to about 30 micrometers. Existing radiation devices that can be used for such purposes, however, have several deficiencies. Specifically, these radiation devices can be very costly and involve high absolute levels of radioactivity that require sophisticated shielding to form the desired radiation beam. Another problem is that the beam from the radioactive source is typically large in relation to the area of the target, and must be shielded and/or collimated (e.g., with optical and/or magnetic lenses) to form the desired radiation beam. Yet another problem is that some of these radiation devices cannot function properly under all conditions and, thus, place constraints on certain targets that are not practicable, such as requiring a vacuum to irradiate a wet biological sample.
There accordingly remains a need in the art for improved radiation devices that can be used to irradiate relatively small areas. It is to the provision of such “microirradiators,” as well as their associated fabrication techniques and applications, that the various embodiments of the present invention are directed.